Current comparator circuits, and particularly CMOS current comparator circuits, that have the ability to determine the direction of an input current and to provide a corresponding voltage or current output are known in the art. Current comparators are important building blocks used in the design of many types of analog and mixed analog/digital integrated circuits. Current comparators are widely used, for example, in data converters. While several designs for current comparators are known in the art, the requirements for improved accuracy and speed, and for lower costs imposed by the state of the art provide an ongoing challenge to constantly improve and simplify those existing designs. In many applications the performance of the current comparator circuit is critical in achieving the overall performance goals for the corresponding functional block or integrated circuit. Most simple existing designs are not able to achieve these performance goals if very high speed operation or accuracy is desired. More elaborate designs or processes other than CMOS processes may be used to achieve high speed and accuracy performance goals, but due to circuit complexity or process characteristics they can add unnecessary power dissipation, increased precious integrated circuit die area, and/or additional expense to the finished integrated circuit.
What is desired, therefore, is a high speed current comparator circuit that is able to achieve high bandwidth, excellent common mode range, high gain, and high output resistance, but is realized with a design that can be economically implemented in an integrated circuit.